Aneurysm stent

ABSTRACT

The present invention relates to an aneurysm stent having a base and connector. The base has a vessel facing side and an aneurysm facing side, and is shaped to cover an aneurysm sufficiently. The connector is coupled to the aneurysm facing side of the base such that when deployed the connector is adapted to extend partially into the aneurysm to anchor the base about the aneurysm and inhibit flow into the aneurysm.

[0001] The present invention claims the benefit of U.S. ProvisionalApplication Serial No. 60/404,422, filed Aug. 19, 2002, titled CEREBRALANEURYSM COIL STENT, incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to the surgical repair of aneurysmsand, more particularly, to a patch that provides a seal between thearterial wall and a neck of the aneurysm to inhibit flow in theaneurysm.

BACKGROUND OF THE INVENTION

[0003] An aneurysm is a blood-filled dilation of a blood vessel. Majorconcerns with aneurysms revolve around rupturing of the arterial wallcausing internal bleeding and clots breaking away from the aneurysmcausing strokes.

[0004] There exist two generally approved methods of treating aneurysms.The first method of treatment includes surgical treatment. The secondmethod of treatment includes endovascular treatment. Surgical removal ofthe aneurysm is sometimes not possible, leaving endovascular treatmentas the only available option. Even when not the only option,endovascular treatment often is preferred because of the reduced risksand complications.

[0005] Conventionally, endovascular treatment of an aneurysm involves“packing” the aneurysm such that an endovascular occlusion is formed.Packing the aneurysm with coils, such as Guglielmi Detachable Coils (orGDCs), helps form an occlusion. While using GDCs is conventional, theaneurysm can be packed with numerous devices, such as, for example,other types of coils, balloons, glues, polymers, clotting agents,liners, or the like.

[0006] Endovascular treatment, while considered less risky than surgicaltreatment, has drawbacks. One drawback of endovascular treatment of theaneurysm includes the potential to over pack the aneurysm. Over packingthe aneurysm can cause the material to enter the parent blood vessel,potentially inhibiting blood flow or generate undesirable pressure inthe aneurysm. Also, some aneurysms have a wide connection to the bloodvessel, a.k.a. wide neck aneurysms. Wide neck aneurysms have theadditional risk that the occluded material will break free of theaneurysm and enter the parent blood vessel, potentially causing blockageof the parent blood vessel. Finally, clotting agents and polymers usedto form occlusions in the aneurysm can seep to the parent blood vesselcausing complications. Balloons and liners are intuitively pleasing as asolution, but have the potential for an inexact fit causingcomplications. For example, a balloon may be over inflated causingunwanted pressure or under inflated causing seepage in the aneurysm.

[0007] While the packing methods described above inhibit blood flow tothe aneurysm, the aneurysm neck typically is open to the parent bloodvessel. Thus, blood continues to flow to the aneurysm. To reduce theblood flow, several devices have been developed to cover the neck areaof the aneurysm.

[0008] U.S. Pat. No. 6,454,780, issued Sep. 24, 2002, to Wallace, titledAneurysm Neck Obstruction Device, shows a device designed to cover orblock the neck of the aneurysm. FIG. 1 shows the Wallace device 10 insome detail. The device 10 is placed inside aneurysm 50 using a catheter46 and deployment tool 44. When inside the aneurysm 50, device 10 haswalls 12 that expand or unfold to contact the inside of the aneurysm 50and block neck 51. But the device resides internal to aneurysm 50allowing blood flow shown by arrow A in the parent vessel 52 to push upagainst the walls 12. The upward pressure of the blood vessel on thewall 12 may allow blood from the parent vessel to seep in aneurysm 50.Also, because the wall is internal to the aneurysm 50, the neck 12 hasthe potential to expand. Other types of internal devices include linersand other neck bridges.

[0009] Devices to block the neck of the aneurysm external to theaneurysm exist also. These devices use the pressure of the blood vesselto help seat the block against the parent vessel wall and shield theneck from the blood vessel. One such device is shown in U.S. Pat. No.6,309,367, issued Oct. 30, 2001, to Boock, titled Aneurysm Shield. TheBoock device is shown in FIG. 2. The Boock device 30 has a cylindricalshaft 32 that covers the neck 37 of the aneurysm 38 and is anchored byanchor rings 34 and 36. While device 30 resides external to the aneurysmit has multiple parts that could break free or deteriorate that residein the parent vessel. While the Boock device 30 seemingly works for itsintended purpose in theory, its relatively large size and surface areamakes its impractical to actually use. In the brain, for example,multiple blood vessels may branch off from the location of an aneurysm.Attempting to use the Boock device would block blood flow to one or moreof the branch vessels as well as the aneurysm, which makes the Boockdevice useful in only limited situations, if any.

[0010] Thus, it would be desirous to develop and improve internal andexternal aneurysm stents.

SUMMARY OF THE INVENTION

[0011] To attain the advantages and in accordance with the purpose ofthe invention, as embodied and broadly described herein, apparatuses toinhibit the flow of blood to an aneurysm comprise a base and connector.The base has a vessel facing side and an aneurysm facing side, and isshaped to cover an aneurysm sufficiently. The connector is coupled tothe aneurysm facing side of the base such that when deployed theconnector is adapted to extend partially into the aneurysm to anchor thebase about the aneurysm and inhibit flow into the aneurysm.

[0012] The foregoing and other features, utilities and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention as illustrated inthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

[0013] The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate embodiments of thepresent invention, and together with the description, serve to explainthe principles thereof. Like items in the drawings are referred to usingthe same numerical reference.

[0014]FIG. 1 shows a prior art aneurysm device;

[0015]FIG. 2 shows a prior art aneurysm device;

[0016]FIG. 3 shows a perspective view of an aneurysm stent deployed in ablood vessel illustrative of the present invention;

[0017]FIG. 4 shows a cross section of a blood vessel with an aneurysmprior to deployment of the aneurysm stent illustrated in FIG. 3;

[0018]FIG. 5 shows a cross section of the aneurysm stent just prior todeployment;

[0019]FIG. 6 shows a cross section of the aneurysm stent mostly deployedabout the aneurysm;

[0020]FIG. 7 shows a cross section of the aneurysm stent deployed;

[0021]FIG. 8 shows a cross section of a portion of a stent consistentwith the present invention;

[0022]FIGS. 9A and 9B show a stent consistent with the presentinvention; and

[0023]FIGS. 10A and 10B show a cross-section of a stent consistent withthe present invention.

DETAILED DESCRIPTION

[0024] Some embodiments of the present invention are described withreference to FIGS. 3 to 10B. FIG. 3 shows an aneurysm stent 300consistent with an embodiment of the present invention deployed. Stent300 is deployed in a parent blood vessel 302, which is shown as anartery but could be a vein a capillary, or the like, about aneurysm 304.A blood flow path from vessel 302 to aneurysm 304 is provided by ananeurysm neck 306. Neck 306 is shown as a narrow neck, but could be awide neck. Aneurysm 304 is shown packed with conventional GDCs 308.While shown as packed with conventional coils, aneurysm 304 could bepacked with any type of packing agent, such as, for example, other typesof coils, balloons, glues, polymers, clotting agents, liners, or thelike. In fact, aneurysm 304 does not need to be packed at all as stent300 blocks blood flow to aneurysm 304. The attachment of stent 300 tocover neck 306 will depend, in part, on the type of material used topack aneurysm 304, if any.

[0025] With reference to FIG. 3, which illustrates aneurysm 304 packedwith conventional GDCs 308, stent 300 includes a base 310, a baseconnection point 312, and a connector 314. Base 310 has opposed sides, avessel side and a wall side (not specifically labeled). The vessel sidecan be covered with a graft material or other biocompatible material.The vessel side may be coated with a material to stimulate cell growthand encourage formation of a pseudointima. The wall side could becovered with an adhesive to assist in seating stent 300 about neck 306by forming a seal between base 310 and vessel 302. Base connection point312 couples base 310 to connector 314. Base connection point 312 doesnot need to exist as a separate component, but is identified forconvenience to distinguish between base 310 and connector 314. Baseconnection point 312 could, as a matter of design choice, be a fittingto connect base 310 and connector 314 if desired. Connector 314 can be aconventional coil material attached to base 312 that extends to GDCs308. When deployed, connector 314 assumes its coiled shape and engagesGDCs 308 to assist in keeping stent 300 seated about neck 306. Connector314 could physically curl around or hook into GDCs 308 for anchoring,but connector 314 could simply pack in aneurysm 304 similar to aconventional GDC. Connector 314 could simply anchor stent 300 in place,but could also contract and pull base 310 snug against vessel 302 tofirmly seat base 310 about aneurysm neck 306 further inhibiting bloodflow to aneurysm 304. While only one base connection point 312 and oneconnector 314 is shown in FIG. 3, multiple connections and connectorsare possible. Also, the connections do not necessarily have to be in thecenter of the stent, but could be offset. It is believed greaterstability will be obtained by symmetrical placement of connectors andconnection points, but asymmetrical placement is possible. Multipleconnectors could be attached to a single connection point as well.

[0026] Referring now to FIGS. 4-7, a method of deploying the stent 300will be described. Referring first to FIG. 4, parent vessel 302 is shownwith aneurysm 304 and neck 306 existing off the main body of vessel 302.Unlike FIG. 3, a second vessel 402 resides about neck 306 forming ajunction 404. While the present invention will be explained inconnection with deploying stent 300 about junction 404, stent 300 couldbe similarly deployed at locations with more or less junctions. First,aneurysm 304 is packed using, for example, conventional GDCs 308 in aconventional manner. Without going in much detail, GDCs 308 are placedby first directing a catheter 406 to the site of aneurysm 304. GDCs 308are passed through catheter 406 and packed in aneurysm 304 in aconventional manner. Once GDCs 308 are placed, stent 300 is passedthrough the same or a different catheter 406 using a guide wire 502(FIG. 5). Stent 300 includes base 310 and connector 314. As can be seen,base 310 is compacted to pass through catheter 406. Also, connector 314enters the packed GDCs 308.

[0027] Referring now to FIG. 5, stent 300 has exited catheter 406 andguide wire 502 can be seen attached to stent 300. Base 310 isapproaching neck 306 and connector 314 has extended in GDCs 308 packedin aneurysm 304. As shown, base 310 can be made of a self-expandingmaterial that begins expanding on exiting catheter 406. Alternatively,base 310 can be made of a material that requires activation or othermanipulation to expand.

[0028] Referring now to FIG. 6, stent 300 is shown in the appropriateposition and guide wire 502 has been withdrawn. Base 310 has expandedsufficiently to mostly block neck 306 and connector 314 has beguncurling, packing, embedding or otherwise anchoring in aneurysm. Forexample, connector 314 can be placed about GDCs 308 as conventionalpacking material, connector 314 can curl and engage GDCs 308, or thelike. While one connector 314 is shown, it would be possible to have twoof more connectors 314. As described in more detail below, a number ofother devices and techniques can be used to anchor stent 300 about theneck.

[0029] Referring now to FIG. 7, stent 300 is shown with base 310 andconnector coils 314 fully deployed. In this case, base 310 is flush withthe wall of vessel 302, wraps around junction 404 and is flush with thewall of vessel 402. Connectors 314 are engaged with GDCs 308 and,optionally, connectors 314 contract in a manner that pulls base 310 intoward GDCs 308 providing a snug seating between base 310 and vessel302.

[0030] The stent 300 could be made of many materials. Some materialincludes conventional graft material. Alternatively, stent 300 could bemade of one or more shaped memory alloys (SMAs) or a combination ofgraft material and SMAs. SMAs are a group of materials that demonstratean ability to return to some previously defined shape or size whensubjected to the appropriate thermal procedure. Generally, thesematerials can be plastically deformed and, upon exposure to thermalmanipulation, will return to the pre-deformation shape. Some SMAmaterial is considered to be two-way shaped memory alloys because theywill return to the deformed shape upon proper thermal activation. SMAsinclude Ag—Cd alloys, Cu—Al—Ni alloys, Cu—Sn alloys, Cu—Zn alloys,Cu—Zn—Si alloys, Cu—Zn—Sn alloys, Cu—Zn—Al alloys, In—Ti alloys, Ni—Alalloys, Ni—Ti alloys, Fe—Pt alloys, Mn—Cu alloys, Fe—Mn—Si alloys, andthe like. As shown by FIGS. 4-7, SMAs would work well for stent 300because, for example, connectors 314 could be shaped with a predefinedcurl that will engage GDCs 308. The SMA could be deformed at apredefined temperature to a straight, or substantially straight, shapeto allow for connectors 314 to penetrate packed GDCs 308 in aneurysm302. Thermal manipulation would cause connector coils 314 to assume theoriginal curled shape that will anchor stent 300 about aneurysm 302 andmay provide a force tending to pull base 310 in towards aneurysm 302further seating stent 300 about aneurysm 302. Similarly, base 310 couldbe made of SMA. In this case, base 310 could be originally shaped toapproximate the shape of the vessel(s) around aneurysm neck 304 to allowfor as close a fit as possible. This would also allow use of stent 300in areas having many vessels branching around the aneurysm.

[0031] As shown in FIGS. 3-7, base 310 is shown having a circular orsemicircular shape. In particular, FIG. 3 illustrates base 310 as a coilof material that expands on deployment. The shape of base 310, however,is largely a function of material, design choice, and the aneurysmlocation. Thus, stent 300 could take many shapes including triangular,rectangular, square, elliptical, conical, spherical, circular,cylindrical, or the like

[0032] The present invention has been described with the aneurysm packedwith conventional GDC coils, as described above, the aneurysm could bepacked with alternative material. For example, if the aneurysm waspacked with a polymer or clotting agent, the connector or anchor couldbe a simple post connected to the stent and embedded in the occlusion.Base 310 connected to the post would be held in place by the occlusion.Further seating force could be supplied by using a material thatcontracts on activation, such as SMAs. If the aneurysm was packed with aliner or balloon, a connection post could be provided on the balloon orliner to allow attaching the stent to the balloon or liner. For example,a balloon inserted in aneurysm 302 could have a flanged lower post(similar to some helium balloons) that connector coil 314 could wraparound. In this case, if, for example, connector coil 314 was made outof SMAs, thermal activation could cause coil 314 to tighten around thepost attached to the balloon and contract. The contraction would beresisted by the flange on the post tending to pull base 310 in towardsaneurysm 302 to assist in seating base 310 about aneurysm 302.Alternatively to a post, the stent could have prongs that extend alongthe inside walls of the aneurysm such that the expanded balloon or linerwould press the prongs against the wall of the aneurysm and seat thestent. Referring to FIG. 8, base 310 could be designed with a clamp 802around an edge 804 of base 310. As shown, clamp 802 could have opposedsurfaces 806 such that when deployed, surfaces 806 move together andgrip vessel 302 at neck 306. A ridge 808 could be provided to assist inthe grip. Clamp 802 would be particularly useful if aneurysm 304 was notpacked with anything.

[0033] Referring to FIGS. 9A and 9B, another stent 900 consistent withthe present invention is shown. Stent 900 includes a base 910 and aconnector 920. Un deployed, connector 920 is a tightly wrapped coil ofmaterial. On deployment, connector 920 unwinds into a bulbous orvolumous area sufficiently to anchor the stent 900. Generally, connector920 would expand to completely fill aneurysm space, but at a minimum theexpansion should be sufficient to prevent connector 920 from pulling outof the aneurysm. As can be appreciated, stent 900 could be used to treatthe aneurysm without packing material. But if packing material were usedto treat the aneurysm, connector 920 would not need to expand as much.

[0034]FIGS. 10A and 10B show another stent 1000 consistent with thepresent invention. FIG. 10A shows a front plan view of a stent 1000 thatincludes a base 1010 and expanded connectors 1020 and 1030. While stent1000 is shown with two orthogonal rings as connectors 1020 and 1030,more rings could be used. Further the rings could be cross-linked orindividual rings. FIG. 10B shows a side plan view of stent 1000 alsowith expanded connectors 1020 and 1030. As can be seen, connectors 1020and 1030, which are shown in the deployed state, expand to form ringsthat act similar to the corkscrew anchor above. Also, while shown asrings any shape is possible, such as diamond, circular, square,triangular, elliptical, helical, or the like.

[0035] While the invention has been particularly shown and describedwith reference to a preferred embodiment thereof, it will be understoodby those skilled in the art that various other changes in the form anddetails may be made without departing from the spirit and scope of theinvention.

We claim:
 1. An apparatus to inhibit flow to an aneurysm, comprising: abase having a vessel facing side and an aneurysm facing side; the basecomprising a shape sufficient to cover an aneurysm; a connector; and theconnector coupled to the aneurysm facing side, wherein the connector isadapted to anchor the base about the aneurysm to inhibit flow into theaneurysm.
 2. The apparatus according to claim 1, wherein the connectoris a coil adapted to pack in the aneurysm.
 3. The apparatus according toclaim 2, wherein the connector is adapted to couple to at least one ofthe group consisting of: GDCs, balloons, liners, polymers, and clottingagents.
 4. The apparatus according to claim 1, wherein: the basecomprises an edge; and the connector has at least a first prong, suchthat the edge and at least the first prong form a clamp that grips thevessel wall to seat the base about the aneurysm.
 5. The apparatusaccording to claim 1, wherein: the base comprises graft material.
 6. Theapparatus according to claim 1, wherein: the base comprisesself-expanding material such that the base can be delivered in a smallpackage and expands on deployment to cover the aneurysm.
 7. Theapparatus according to claim 6, wherein the base also comprises graftmaterial.
 8. The apparatus according to claim 1, wherein the connectorcomprises at least one coil adapted to engage GDCs packed in theaneurysm.
 9. The apparatus according to claim 8, wherein the at leastone coil is made of at least a first shaped memory alloy.
 10. Theapparatus according to claim 9, wherein the at least one coil isdeformed such that on thermal treatment the at least one coil engagesGDCs and provides a force tending to seat the base about the aneurysm.11. The apparatus according to claim 1, wherein the base is at least oneof a triangular shape, a circular shape, a conical shape, a sphericalshape, an elliptical shape, a rectangular shape, and an irregular shape.12. The apparatus according to claim 1, wherein the base residescompletely in the vessel.
 13. The apparatus according to claim 1,wherein the aneurysm facing side is coated with an adhesive.
 14. Theapparatus according to claim 1, wherein the connector comprises a postto be anchored in an occlusion in the aneurysm.
 15. The apparatusaccording to claim 1, wherein the connector comprises at least one prongextending along an interior wall of the aneurysm, the at least one prongadapted to be held in place by at least one of a balloon or linerinserted in the aneurysm.
 16. The apparatus according to claim 1,wherein the base comprises at least one base coil arranged to expand ondeployment.
 17. The apparatus according to claim 16, wherein the atleast one base coil expands on activation.
 18. The apparatus accordingto claim 16, wherein the at least one base coil is arranged in the shapeof a spiral.
 19. The apparatus according to claim 16, wherein the atleast one base coil comprises a shaped memory alloy that is activated onthermal manipulation.
 20. The apparatus according to claim 1, whereinthe vessel facing side is coated with a material to stimulate cellgrowth and encourage formation of a pseudointima.
 21. The apparatusaccording to claim 1, wherein the connector is a tightly wound coil ofmaterial that expands to a corkscrew shape to anchor the stent.
 22. Theapparatus according to claim 1, wherein the connector is a plurality ofrings that expand to anchor the stent.
 23. The apparatus according toclaim 22, wherein the plurality of cross-linked rings are orthogonal.24. An aneurysm stent, comprising: a base; at least one connectorcoupled to the base; the at least one connector adapted to be insertedinto an aneurysm packed with GDCs and, upon insertion, to curl and packinto the aneurysm.
 25. The aneurysm stent according to claim 24,wherein: the at least one connector is coupled to a geometric center ofthe base.
 26. The aneurysm stent according to claim 24, wherein: the atleast one connector is at least two connectors, each connector extendingin the aneurysm.
 27. The aneurysm stent according to claim 26, wherein:the at least two connectors are coupled to the base in a symmetricalmanner.
 28. The aneurysm stent according to claim 24, wherein the atleast one connector is made of a first shaped memory alloy.
 29. Theaneurysm stent according to claim 28, wherein the base is made of asecond shaped memory alloy.
 30. The aneurysm stent according to claim29, wherein the first shaped memory alloy and the second shaped memoryalloy are the same.
 31. The aneurysm stent according to claim 30,wherein the first shaped memory alloy and the second shaped memory alloyare nitinol.
 32. The aneurysm stent according to claim 24, wherein thebase has a vessel side and an aneurysm side, the vessel side comprises alayer of biocompatible material that promotes permanent fixation of thestent
 33. The aneurysm stent according to claim 32, wherein thebiocompatible material is a graft coated with a material to stimulatecell growth and encourage formation of a pseudointima.
 34. The aneurysmstent according to claim 32, wherein the aneurysm side has a layer ofadhesive.
 35. An apparatus to inhibit flow to an aneurysm, comprising: abase having a vessel facing side and an aneurysm facing side; the basecomprising a shape sufficient to cover an aneurysm; and means foranchoring the base about the aneurysm to inhibit flow into the aneurysm.36. The apparatus according to claim 35, wherein the means for anchoringcomprises: at least one of a coil, a post, a prong, and a clamp.
 37. Amethod for obstructing the flow of blood through the neck of ananeurysm, the method comprising the steps of: passing a catheter to thesite of an aneurysm; inserting an anchor into the aneurysm; deploying ananeurysm base to block the neck of the aneurysm; and anchoring theaneurysm base about the neck of the aneurysm using the anchor to inhibitthe flow of blood in the aneurysm.
 38. The method according to claim 37,further comprising the step of: packing material in the aneurysm to forman occlusion.
 39. The method according to claim 38, wherein theanchoring step includes engaging the anchor with the packed material.40. The method according to claim 38, wherein the anchoring step furtherincludes the step of: providing a seating force to assist in seating theaneurysm base about the neck of the aneurysm.
 41. The method accordingto claim 37, further comprising the steps of: providing an adhesivecoating on the aneurysm base; and adhering the aneurysm base to thevessel during deployment.
 42. An aneurysm stent, comprising: a base; atleast one connector coupled to the base; the at least one connectoradapted to be inserted into an aneurysm and, upon insertion, to anchorthe base about a neck of the aneurysm.
 43. The aneurysm stent accordingto claim 42, wherein the at least one connector comprises: at least onetightly wound coil that extends from the base into the aneurysm; the atleast one tightly wound coil expands after insertion to pack theaneurysm and anchor the stent.
 44. The aneurysm stent according to claim43, wherein the at least one tightly wound coil expands into a corkscrewshape.
 45. The aneurysm stent according to claim 42, wherein the atleast one connector comprises at least one of a plurality of coils, aplurality of prongs, and a plurality of posts.
 46. The aneurysm stentaccording to claim 45, wherein the plurality of cross-linked coils areorthogonal.